相关疑难解决方法(0)

我需要检查URL是否存在.我想为此编写一个servlet,即检查URL是否存在.如果输入的URL不存在,则应返回一些消息.

这是我用来验证的代码,在服务器上存在或不存在URL,但始终不存在但链接仍然存在

在我的代码中我犯了错误,为什么我总是"不存在!"

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);     

        String customURL = "http://www.desicomments.com/dc3/08/273858/273858.jpg";
        boolean bResponse = exists(customURL);

        if (bResponse==true)
        {
            Toast.makeText(MainActivity.this, "File exists!", Toast.LENGTH_SHORT).show();      
        }
        else
        {           
            Toast.makeText(MainActivity.this, "File does not exist!", Toast.LENGTH_SHORT).show();
        }   

    }

    public static boolean exists(String URLName){
        try {
            HttpURLConnection.setFollowRedirects(false);
            HttpURLConnection con =  (HttpURLConnection) new URL(URLName).openConnection();
            con.setRequestMethod("HEAD");
            return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
        }
        catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

}

我希望我的Android程序使用其URL检查远程服务器中是否存在文件(例如index.php).即如果我单击按钮,它应检查是否存在URL.如果是,它应该加载相同的URL,否则显示消息"文件不存在!"

我做了这样的事情:

   private OnClickListener cameraListener9=new OnClickListener(){
    public void onClick(View v){

    idNo=editText.getText().toString();

    String URLName ="http://blahblah/kufpt/upload_test/"+ idNo + "/index.php";

    boolean bResponse = exists(URLName);
    if (bResponse==true)
    {
        Toast.makeText(MainActivity.this, "FILE EXISTS" , Toast.LENGTH_SHORT).show();
        WebView mWebView =(WebView)findViewById(R.id.webView);
        mWebView.loadUrl(URLName);

    }
    else
        Toast.makeText(MainActivity.this, "File does not exist!", Toast.LENGTH_SHORT).show();

    }
};

/*这是要调用以检查index.php文件是否存在或已创建的函数*/如使用其URL检查远程服务器上是否存在文件中的建议

    public static boolean exists(String URLName){
    try {
      HttpURLConnection.setFollowRedirects(false);
      // note : you may also need
      //HttpURLConnection.setInstanceFollowRedirects(false)

      HttpURLConnection con =  (HttpURLConnection) new URL(URLName).openConnection();
      con.setRequestMethod("HEAD");
      return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
     }
    catch (Exception e) {
       e.printStackTrace();
       return …